Estimating Snow Depth and Leaf Area Index Based on UAV Digital Photogrammetry
Abstract
:1. Introduction
2. Materials and Methods
2.1. Study Test Sites
2.2. UAV Monitoring
2.3. Photogrammetric Processing
2.4. Snow Depth Data Acquisition and Analysis
2.5. LAI Assessment
3. Results
3.1. Study Sites and Data Acquisition
3.2. UAV-Based Snow Depth Estimations vs. Manual Snow Depth
3.3. Optical Indirect Estimation of LAIeff
3.4. Relationship between Indirect Winter LAIeff and Snow Depth
4. Discussion
4.1. Snow Depth Validation of Open vs. Forest Site
4.2. Validation of the Winter LAI
4.3. Validation between Snow Depth and LAI
5. Conclusions
Author Contributions
Funding
Conflicts of Interest
References
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UAV Details | |
UAV type | ARF-OktoXL |
Dimension | 73 × 73 × 36 |
Payload | 2500 g |
Gimbal | MK HiSight SLR2 |
Max altitude | 100 m |
Max distance | 100 m |
Flight time | Max. 45 min |
Realistic flight time | 15–28 min |
Navigation | NaviCtrl V2.1 (IMU, barometer, GPS controller), MK-GNSS V4 GPS receiver (American GPS satellites, the European Galileo system, the Russian Glonass satellite or the Chinese BeiDou satellite system) |
Wireless communication | Graupner MC-32 HoTT remote controller |
LiPo battery | Vislero 5000, 14.8V 4S1P Flat |
Camera Details | |
Camera type | Lumix DMX-GX7 |
Sensor type | 16MP Live MOS sensor |
Sensor size (mm) | 17.3 × 13.0 mm (in 4:3 aspect ratio) |
Focal length | 20 mm |
Sensor resolution (MP) | 16 |
ISO range | 125–25,600 |
Weight (g) | 402 (g) |
Input Parameter GLA | Value |
---|---|
Cloudiness index | 0.5 |
Spectral fraction (0.25–25 μm) | 1 |
Beam fraction | 0.5 |
Clear-sky transmission coefficient | 0.5 |
Solar constant (Wm-2) | 1367 |
Flight Campaign | Date | Images | Flight Height [m] | Covered Area [km2] | Mean Ground Resolution [cm/pix] | Number of GCPs | Number of CPs | X Error RMSE [m] | Y Error RMSE [m] | Z Error RMSE [m] | XY Error RMSE [m] | Total RMSE [m] |
---|---|---|---|---|---|---|---|---|---|---|---|---|
Filipova Hut (open site; snow ablation) | 24.3. 2017 | 963 | 62.2 | 0.056 | 1.16 | 8 | 6 | 0.041 | 0.039 | 0.055 | 0.056 | 0.079 |
Filipova Hut (snow-free) | 30.4. 2017 | 1130 | 72.8 | 0.036 | 1.98 | 9 | 6 | 0.066 | 0.035 | 0.036 | 0.075 | 0.084 |
Ptaci brook (forest site; snow accumulation) | 3.3. 2017 | 906 | 40.3 | 0.012 | 0.73 | 4 | 5 | 0.030 | 0.037 | 0.059 | 0.047 | 0.076 |
Ptaci brook (snow ablation) | 15.3. 2017 | 1024 | 46 | 0.014 | 0.84 | 5 | 5 | 0.041 | 0.050 | 0.026 | 0.065 | 0.067 |
Ptaci brook (snow-free) | 30.4. 2017 | 564 | 60.7 | 0.015 | 1.12 | 5 | 4 | 0.046 | 0.030 | 0.056 | 0.055 | 0.078 |
HGCP-HUAV (One Pixel-Base; z values) | Open Area (Snow Ablation) n = 14 | Forest (Snow Accumulation) n = 9 | Forest (Snow Ablation) n = 10 |
Mean bias [m] | 0.22 | 0.21 | 0.29 |
SD [m] | 0.11 | 0.19 | 0.19 |
MAE [m] | 0.09 | 0.16 | 0.13 |
RMSE [m] | 0.08 | 0.15 | 0.09 |
HT-HUAV (Mean Value of 1 m Radius; z values) | Open Area (Snow Ablation) n = 105 | Forest (Snow Accumulation) n = 36 | Forest (Snow Ablation) n = 36 |
Mean bias [m] | 0.08 | 0.14 | 0.14 |
SD [m] | 0.14 | 0.29 | 0.27 |
MAE [m] | 0.19 | 0.24 | 0.22 |
RMSE [m] | 0.16 | 0.32 | 0.31 |
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Lendzioch, T.; Langhammer, J.; Jenicek, M. Estimating Snow Depth and Leaf Area Index Based on UAV Digital Photogrammetry. Sensors 2019, 19, 1027. https://doi.org/10.3390/s19051027
Lendzioch T, Langhammer J, Jenicek M. Estimating Snow Depth and Leaf Area Index Based on UAV Digital Photogrammetry. Sensors. 2019; 19(5):1027. https://doi.org/10.3390/s19051027
Chicago/Turabian StyleLendzioch, Theodora, Jakub Langhammer, and Michal Jenicek. 2019. "Estimating Snow Depth and Leaf Area Index Based on UAV Digital Photogrammetry" Sensors 19, no. 5: 1027. https://doi.org/10.3390/s19051027
APA StyleLendzioch, T., Langhammer, J., & Jenicek, M. (2019). Estimating Snow Depth and Leaf Area Index Based on UAV Digital Photogrammetry. Sensors, 19(5), 1027. https://doi.org/10.3390/s19051027